Use of salts of sulfonated alkenyl or alkenyl(poly)-oxyalkyl phosphates as emulsifiers for emulsion polymerization

ABSTRACT

The use of salts of sulphonated alkenyl or alkenyl(poly)oxyalkyl phosphates of formula (I): [R&lt;1&gt;O-(CnH2nO)x-][R&lt;2&gt;O-(CnH2nO)y-][R&lt;3&gt;O-(CnH2nO)z-]P=O, in which R&lt;1&gt; is a group of formula (IIa): CH3-(CH2)a-CH(OH)-(CH2)b-CH(SO3M)-(CH2)c-CH2- or (IIb): CH3-(CH2)a-CH(SO3M)-(CH2)B-CH(OH)-(CH2)c-CH2-, or a residue formed by the separation of a water molecule from the group of formula (IIa) or (IIb); R&lt;2&gt; and R&lt;3&gt;, which may the same or different, are hydrogen or a residue with the definition given for group R&lt;1&gt;; n is the number 2 and/or 3; x, y and z, which may be the same or different, are numbers in the range from 0 to 100 and especially 0 to 30; a, b and c are numbers in the range from 0 to 18, where the sum of a, b and c is a number in the range from 12 to 18; and M is an alkali or ammonium ion or an equivalent of an alkaline earth ion; as emulsifiers provides outstanding results in emulsion polymerisation with special reference to coagulate formation.

This invention relates to the use of salts of sulfonated alkenyl oralkenyl(poly)oxyalkyl phosphates corresponding to formula I

    [R.sup.1 O--(C.sub.n H.sub.2n O).sub.x-- ][R.sup.2 O--(C.sub.n H.sub.2n O).sub.y --][R.sup.3 O--(C.sub.n H.sub.2n O).sub.z --]P═O(I)

in which

R¹ is a group corresponding to formula IIa or IIb

    CH.sub.3 --(CH.sub.2).sub.a --CH(OH)--(CH.sub.2).sub.b --CH(SO.sub.3 M)--(CH.sub.2).sub.c --CH.sub.2 --                        (IIa)

or

    CH.sub.3 --(CH.sub.2).sub.a --CH(SO.sub.3 M)--(CH.sub.2).sub.b --CH(OH)--(CH.sub.2).sub.c --CH.sub.2 --                  (IIb)

or a residue formed by elimination of one water molecule from the groupcorresponding to formula IIa or IIb,

R² and R³ may be the same or different and represent hydrogen or aresidue having the meaning defined for the group R¹,

n is the number 2 and/or 3,

x, y and z may be the same or different and represent numbers of 0 to100 and, more particularly, 0 to 30,

a, b and c are numbers of 0 to 18, the sum of a, b and c being a numberof 12 to 18, and

M is an alkali metal or ammonium ion or an equivalent of analkaline-earth metal ion,

as emulsifiers for emulsion polymerization.

Emulsifiers which have been described for the emulsion polymerization ofpolymerizable monomers containing olefinic double bonds include variousionic or nonionic emulsifiers, for example alkylaryl sulfonates,nonylphenol ethoxylates and ethylene oxide/propylene oxide blockcopolymers, cf. Technische Broschure RES/VVX/4 (G), 3rd Edition, 1976,published by Shell-Chemie; α-sulfofatty acid esters, cf. DE-A 33 39 407,tertiary hydroxyalkyl amines, cf. DE-A 33 37 640, adducts of ethyleneoxide with aliphatic vicinal diols containing 8 to 25 carbon atoms, cf.DEA 33 19 782, polyethyleneoxy sulfonates, cf. EP-A 0 026 932, and fattyalcohol polyethyleneoxy phosphates, cf. the emulsifiers DISPONIL® AEP5300, AEP 5325 and AEP 8100 of Henkel KGaA, Dusseldorf.

The above-mentioned surfactants show various disadvantages when used foremulsion polymerization. For example, the polyethyleneoxy sulfonatesaccording to EP 0 026 932 cause intensive foaming in water-based systemscontaining them and, in addition, are expensive to produce. Fattyalcohol polyethyleneoxy phosphates do not have pronounced emulsifierproperties and, accordingly, are only used in relatively highconcentrations or in conjunction with other, stronger emulsifiers.

The present invention is based on the observation that salts ofsulfonated alkenyl or alkenyl(poly)oxyalkyl phosphates, which are alsoreferred to in short hereinafter as phosphate sulfonates, are a group oflow-foaming surfactants which are easy to produce and which areeminently suitable as emulsifiers for emulsion polymerization. Thephosphate sulfonates corresponding to general formula I, which mayformally be regarded as partial or full esters of phosphoric acid Withsulfonates of unsaturated fatty alcohols or with sulfonates of adductsof ethylene oxide and/or propylene oxide with unsaturated fattyalcohols, are known from DE-A 38 02 815(U.S. Pat. No. 5,041,597), towhich reference is hereby specifically made. They may be obtained bysulfonation of phosphoric acid esterified with fatty alcohols, such asoleyl, palmitoleyl, linoleyl, gadoleyl and/or erucyl alcohol or thetechnical mixtures thereof typically used in oleochemistry (thephosphoric acid may be partly or completely esterified or may be presentas a mixture of partial and full esters) with gaseous sulfur trioxide insuitable reactors and neutralization of the sulfonation products withbases. Internal sulfonate groups are thus introduced into thehydrocarbon radicals emanating from the unsaturated fatty alcohols.

The structure of the phosphate sulfonates of general formula I to beused in accordance with the invention has not yet been fully elucidated.By analogy with sulfonated olefins, it is assumed that one hydroxylgroup and one sulfonate group is introduced into the alkyl chain perdouble bond of the unsaturated fatty alcohol radicals in the sulfonationand subsequent hydrolysis of the sulfonation products, structurescorresponding to general formula IIa and IIb being formed. An alkenylradical substituted by a sulfonate group can also be formed from thesestructures by elimination of one molecule of water. A mixture of thecompounds mentioned may even be present.

The phosphate sulfonates of general formula I to be used in accordancewith the invention are suitable as emulsifiers in the emulsionpolymerization of virtually all industrially important, substantiallywater-insoluble monomers. Typical examples of such monomers are aromaticvinyl compounds, for example styrene, divinyl benzene or vinyl toluene,polymerizable olefins and diolefins, such as propene, butadiene orisoprene, esters of acrylic or methacrylic acid with linear or branchedC₁₋₁₈ alcohols and, more particularly, C₁₋₈ alcohols, preferably methylesters, ethyl esters, butyl esters and ethylhexyl esters thereof, vinylesters of C₂₋₁₂ acids, more particularly vinyl acetate, vinylpropionate, vinyl-2-ethyl hexanoate and vinyl laurate, vinyl alkylethers containing C₁₋₁₈ alkyl groups, vinyl chloride, vinylidenechloride and the like. The monomers mentioned above may behomopolymerized or copolymerized with others of the compounds listedabove in the presence of the phosphate sulfonates to be used inaccordance with the invention. In addition, copolymerizations may becarried out involving up to 50% by weight other monomers which,basically, are partly or completely soluble in water, for exampleacrylonitrile, methacrylonitrile, semiesters of maleic or fumaric acidcontaining 1 to 8 carbon atoms, acrylic acid, methacrylic acid, maleicacid, fumaric acid, crotonic acid and/or itaconic acid. A mixture ofethylhexyl acrylate, methyl methacylate and (meth)acrylic acid is atypical example of such systems.

In practice, the aqueous dispersions to be prepared using the phosphatesulfonates corresponding to general formula I contain 15 to 75% byweight polymerized monomers (dry residue) in water or water-solubleorganic solvents. Although a dry residue in the range from 20 to 60% byweight is preferred, aqueous dispersions containing less than 50% byweight dry residue can also be prepared for special applications. Theemulsion polymerization processes mentioned above may also be carriedout using other typical polymerization auxiliaries, more particularlyinitiators, for example inorganic peroxide compounds, such as potassiumor ammonium persulfate or hydrogen peroxide, and organic peroxidecompounds or organic azo compounds providing they can be used for theemulsion polymerization. The initiators are used in typical quantities,i.e. in quantities of 0.05 to 2% by weight and preferably in quantitiesof 0.1 to 0.5% by weight. Other suitable auxiliaries are buffers, forexample sodium hydrogen carbonate, sodium pyrophosphate or sodiumacetate which may be used in quantities of up to 2% by weight.Accelerators, such as formaldehyde sulfoxylate, may also be used. Othersuitable auxiliaries are molecular weight regulators of the type usedfor emulsion polymerization, for example butanol or even organic thiocompounds, such as mercaptoethanol, thioglycolic acid, octyl mercaptanor tert. dodecyl mercaptan. The polymerization processes may be carriedout by any of the methods normally used for emulsion polymerization, forexample by introducing all the reactants together, by monomer inflow orby emulsion inflow. In general, the temperature of the polymerizationmedium is kept in the range from 40° to 100° C. and preferably in therange from 50° to 90° C. A pH value of 3 to 9 is best maintained,although emulsion polymerization may also be carried out at lower pHvalues by virtue of the fact that the sulfonate groups cannot besaponified with the compounds according to the invention.

The above-mentioned emulsion polymerization processes are best carriedout in coolable and heatable reactors equipped with a stirrer and atemperature measuring system, for example in stirred pressure tanks.Multicoil reactors or so-called loop reactors may also be used.

On completion of polymerization, the polymer dispersion is best cooledand removed from the reactor through sieves. If the reaction productsare to be isolated as solid products, the polymer dispersion is bestprecipitated or spray-dried. However, the dispersions obtained in thepolymerization process are preferably directly used as binders forpaints, adhesives, paper coating compositions and other coatingcompounds.

Other conditions for emulsion polymerization processes using thephosphate sulfonates of general formula I to be used in accordance withthe invention may be adapted to meet particular requirements or freelyselected by the expert in the usual way. General specialist knowledge onthe subject of emulsion polymerization may be found, for example, in E.W. Duck, Encyclopedia of Polymer Science and Technology, Vol. 5, pages801-856, John Wiley & Sons, New York (1966) and in the literature citedtherein. Reference is also made to F. Holscher, Dispersionensynthetischer Hochpolymere (Dispersions of Synthetic High Polymers),Part 1, Springer Verlag, Berlin/Heidelberg/New York (1969) and to K. O.Calvert (Editor), Polymer Latices and their Applications, AppliedScience Publishers Ltd., London (1982); A. Schmidt, Methoden derOrganischen Chemie (Houben-Weyl), 4th Edition, Vol. E 20,Makromolekulare Stoffe, Part 1, pages 227-268, Stuttgart (1987).

One preferred embodiment of the invention is characterized by the use ofphosphate sulfonates corresponding to general formula I or IIa or IIb,in which R¹ is a sulfonated oleyl group, R² and R³ are hydrogen or asulfonated oleyl group, n is the number 2 and x, y and z are numbers of0 to 20 and, more particularly, 0 to 10 and a, b and c are as definedabove.

The term "ammonium ion" used in the foregoing also encompassesprotonated mono-, di- and tri-C₁₋₄ -alkyl and C₁₋₄ -hydroxyalkyl amines.However, phosphate sulfonates of general formula I or IIa and IIb, inwhich M is a sodium ion and R¹, R², R³, a, b, c, n, x, y and z are asdefined above, are preferred.

In another advantageous embodiment of the invention, the phosphatesulfonates corresponding to general formula I are used in a quantity of0.5 to 10% by weight, preferably in a quantity of 1 to 5% by weight and,more preferably, in a quantity of 1 to 3% by weight, based on themonomers to be used. In addition, it is particularly preferred to usethe phosphate sulfonates of general formula I in the emulsionpolymerization of polymerizable monomers containing olefinic doublebonds, more particularly (meth)acrylic acid and derivatives thereof orvinyl esters.

Although the phosphate sulfonates of general formula I to be used inaccordance with the invention have very good properties when used assole emulsifiers, they may also be used together with other anionicco-emulsifiers.

Suitable anionic co-emulsifiers are paraffin sulfonates, alkyl benzenesulfonates, alkyl naphthalene sulfonates, soaps of linear or branched,saturated or unsaturated fatty acids, fatty alcohol and syntheticalcohol sulfates, alkyl diphenyl ether disulfonates, sulfosuccinic acidmonoesters and diesters of linear, branched or cyclic alcohols and,quite generally, sulfates, sulfonates, sulfosuccinates, isethionates,phosphates and ether carboxylic acids of the nonionic emulsifiersmentioned below. Where the emulsifiers to be used in accordance with theinvention are used together with other anionic emulsifiers, it ispreferred to keep the total quantity of emulsifier below 5% by weight,based on monomers.

The phosphate sulfonates to be used in accordance with the invention mayalso be used in combination with nonionic co-emulsifiers. This can leadto dispersions having increased stability, for example to shear forces,temperature influences and electrolytes. The nonionic emulsifiers areadded in quantities of 0.5 to 5% by weight and preferably in quantitiesof 1 to 3% by weight, based on monomers. The nonionic emulsifiers may beintroduced at the beginning of polymerization or in the course ofpolymerization. In another variant, a pre-emulsion is prepared using thenonionic emulsifiers and is added in the course of polymerization.Nonionic emulsifiers may also be added to the dispersions obtained usingthe phosphate sulfonates of general formula I for the purpose ofpost-stabilization. Typical examples of nonionic emulsifiers are

linear, branched, cyclic, saturated and unsaturated alkyl polyglycolethers, more particularly fatty alcohol polyglycol ethers;

mono-, di- and trialkylaryl polyglycol ethers, more particularly octyland nonyl phenol polyglycol ethers, dinonyl phenol polyglycol ethers,triisobutyl phenol polyglycol ethers;

aryl polyglycol ethers, for example reaction products of phenol with 3to 10 mol ethylene oxide;

polyglycol ethers of hydroxyalkanols, for example according to DE-A 3319 782;

end-capped alkyl or alkylaryl polyglycol ethers, for example accordingto DE-A 35 30 301 and DE-A 36 43 896;

carboxylic acid polyglycol esters, more particularly fatty acidpolyglycol esters;

fatty acid alkanolamide/ethylene oxide adducts, more particularlycoconut oil fatty acid monoethanolamide/ ethylene oxide adducts;

ethylene oxide/propylene oxide block polymers;

sorbitan esters, more particularly sorethoxylated bitan monolaurate +20mol ethylene oxide;

ethoxylated fatty amines.

The phosphate sulfonates of general formula I to be used in accordancewith the invention may also be used together with protective colloids.Typical examples of such protective colloids are completely or partlysaponified homopolymers and/or copolymers of vinyl acetate, for examplepartly saponified polyvinyl acetate, or partly saponified copolymers ofvinyl acetate and vinyl ethers. Preferred copolymers contain 1 to 4carbon atoms in the ether part of the polyvinyl ether. Other protectivecolloids may be derived from polysaccharides. Thus, cellulose ethers,such as hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethylcellulose, methyl cellulose, ethyl cellulose or cellulose mixed ethers,are particularly suitable. Polyacrylamide and copolymers thereof withacrylic acid, acrylonitrile or acrylates are also suitable. Condensatesof naphthalene sulfonate acid and formaldehyde or other water-solubleformaldehyde resins, more particularly urea/formaldehyde resins, mayalso be used. Finally, casein, gelatine, gum arabic and natural starchand substituted starch derivatives, such as hydroxyethyl starch, aresuitable protective colloids.

So-called copolymerizable emulsifiers--better referred to as stabilizingmonomers--may also be used together with the emulsifiers to be used inaccordance with the invention and include, for example, vinyl sulfonate,allyl sulfonate, 2-acrylamido-2-methyl propane sulfonic acid, vinylphosphonic acid and also acrylates and methacrylates of nonionicemulsifiers or styrene sulfonic acid.

The invention is illustrated by the following Examples.

The production of phosphate sulfonates of general formula I to be usedin accordance with the invention and the methods used to test thepolymer dispersions obtained in accordance with the invention will firstbe explained.

1. Tested phosphate sulfonates of general formula I (internallysubstituted oleyl phosphate sulfonates)

a) oleyl phosphate sulfonate Na salt (from oleyl alcohol having aniodine value of approx. 80)

b) oleyl phosphate sulfonate Na salt (from oleyl alcohol having aniodine value of 108)

The oleyl phosphate sulfonates mentioned above are referred tohereinafter as OPS 80 and OPS 108.

2. Preparation of the oleyl phosphate sulfonates

a) OPS 80

Preparation of the oleyl phosphate:

420 g (1.5 mol) technical oleyl alcohol present in admixture with smallamounts of cetyl alcohol (HD Ocenol® 80/85: iodine value 89, OH value205) were introduced into a 1-liter three-necked flask equipped with astirrer and thermometer. At a temperature of 60° to 70° C., 71 g (0.5mol) phosphorus pentoxide were uniformly introduced over a period of 2hours by means of a powder metering unit protected against atmosphericmoisture. Following an after-reaction time of 2 hours at 70° C., 10 mlwater were added and the reaction mixture was stirred for another 3hours at 90° C.

490 g of a dark-colored oil having the following characteristic datawere obtained:

    ______________________________________                                        Monoester             43.3% by weight                                         Diester               38.4% by weight                                         Triester              3.4% by weight                                          H.sub.3 PO.sub.4      1.7% by weight                                          Free alcohol          13.0% by weight                                         H.sub.2 O (Fischer)   0.15% by weight                                         Iodine value          74                                                      Average molecular weight                                                                            451                                                     Double bond equivalent per mol                                                                      1.3                                                     phosphate                                                                     ______________________________________                                    

Production of the oleyl phosphate sulfonate Na salt:

225 g (0.5 mol) oleyl phosphate were introduced into a 1 litersulfonation flask equipped with a mechanical stirrer, gas inlet pipe andjacket cooling and were reacted at 35° C. with 68 g (0.85 mol) SO₃corresponding to a 30% excess based on the double bond equivalents. TheSO₃ was driven out by heating from a corresponding quantity of oleum,diluted with nitrogen to a concentration of 5% by volume and introducedinto the phosphoric acid ester over a period of 31 minutes during whichthe temperature of the reaction mixture was kept below 50° C. bycooling. After the sulfonation, the reaction mixture was cooled to 10°C., stirred into a dilute solution of 40 g (1 mol) NaOH in 700 ml waterand subsequently hydrolyzed on a steam bath for 4 hours at 95° to 100°C. After cooling to 20° C., the pH value of the reaction mixture wasadjusted to 7.0 by addition of HCl solution.

Characteristic data of the product:

    ______________________________________                                        Anionic surfactant (two-phase titration                                                               16% by weight =                                       method corresponding to Einheitsmethode                                                               0.30 mval/g                                           DGF-H-III-10)                                                                 Unsulfonated components 1% by weight                                          (DGF-GIII-6b)                                                                 Na.sub.2 SO.sub.4       1% by weight                                          Na.sub.3 PO.sub.4       <0.1% by weight                                       H.sub.2 O (Fischer)     82% by weight                                         Total sulfur            1.2% by weight                                        Average molecular weight                                                                              539                                                   Klett color value       135                                                   ______________________________________                                    

b) OPS 108

Preparation of the oleyl phosphate

The procedure described in 2a for the preparation of the oleyl phosphasewas repeated using 420 g (1.5 mol) of a technical oleyl alcohol havingan iodine value of 108. Approx. 485 g of a yellowish oil were obtained.

Characteristic data of the product:

    ______________________________________                                        Monoester            42.9% by weight                                          Diester              38.2% by weight                                          Triester             3.2% by weight                                           Phosphoric acid (free)                                                                             1.5% by weight                                           Fatty alcohol (free) 13.0% by weight                                          Water (Fischer)      0.10% by weight                                          Iodine value         83                                                       Average molecular    453                                                      Double bond equivalent                                                                             1.3                                                      ______________________________________                                    

Preparation of the oleyl phosphate sulfonate Na salt

The procedure described in 2a for the preparation of the oleyl phosphatesulfonate Na salt was repeated using 226 g (0.5 mol) of the oleylphosphate obtained as described above.

Characteristic data of the product:

    ______________________________________                                        Anionic surfactant content                                                                    15.9% by weight = 0.029 mEq/g                                 Unsulfonated components                                                                       1% by weight                                                  Sodium sulfate  1% by weight                                                  Sodium phosphate                                                                              0.1% by weight                                                Water           82.1% by weight                                               Average molecular weight                                                                      541                                                           ______________________________________                                    

3. Tests for polymer dispersions obtained in accordance with theinvention

a) Coagulate content after production

The prepared dispersion and any coatings formed on the reaction vesseland stirrer were poured through a Schwegmann tared Perlon sieve bag(mesh width 80 microns). The sieve bag together with any coagulatepresent was dried for 24 h at 105° C. and the coagulate was determinedby differential weighing.

b) Solids content

Sartorius type 709301dry residue determination balance. The solidscontent was determined at stage 7 with a drying time of 20 minutes. Thequantity weighed in was 5 g.

c) pH value

The pH value was determined with a commercially available pH meter.

d) Viscosity

Viscosity was measured with a Brookfield RVT viscosimeter at 25° C.(spindle 1, 10 r.p.m.⁻¹).

e) Minimum film-forming temperature (MFT)

The MFT was determined with a Coesfeld film-forming and blockingtemperature tester in accordance with DIN 53787.

f) Mechanical stability

The mechanical stability of the dispersion was tested with a type HM 5UB 2 klaxon stirrer with addition of a foam inhibitor in accordance withASTM D 1706.

g) Foaming test

A test liquid consisting of 50 g of the polymer dispersion and 450 gfully deionized water was poured into a 2 liter measuring cylinderequipped with a heating jacket. By means of a flow inducer (Heidolphtype RG-L 85), the test liquid was continuously circulated at 25° C. ata throughput of 3 1/min. Using a glass tube, the test liquid was takenin from the bottom of the measuring cylinder and was returned to thecylinder through a second glass tube. After a maximum time of 10minutes, circulation was terminated and the maximum foam volume (totalvolume) was read off. The total volume was read off at time intervals of1, 2, 3, 5, 10 and 20 minutes and the values determined were recorded ina volume/time graph.

Example 1

Copolymerization of a mixture of vinyl acetate and tert. monocarboxylicacid vinyl ester

The monocarboxylic acid vinyl ester was a commercially available mixtureof a vinyl ester of isomeric, synthetic, saturated, substantiallytertiary monocarboxylic acids having a chain length of C₁₀, described inTechnische Broschure AES/VVX/4 (G), 3rd Edition, October 1976, publishedby Shell-Chemie, and is referred to hereinafter by the same abbreviationas used there, namely VeoVa 10.

The copolymerization was carried out in a closed, heatable 2 literplane-ground beaker equipped with a V4A anchor stirrer (stirring speed100 to 150 r.p.m.), feed vessels and a reflux condenser.

The following reaction components were first separately prepared:

Component I:

191.5 g fully deionized water

1.3 g OPS 80 (100% active substance)

0.5 g potassium peroxodisulfate (starter)

0.2 g borax (buffer).

Component II:

282.3 g fully deionized water

0.8 g OPS 80 (100% active substance)

17.1 g of a commercially available adduct of 30 mol ethylene oxide withnonylphenol (70% active substance; co-emulsifier)

1.9 g potassium peroxodisulfate

2 1 g borax

Component III:

330.1 g vinyl acetate

143.5 g VeoVa 10

4.8 g acrylic acid

For pH adjustment:

23.9 g ammonium carbonate solution (10%).

Component I was initially introduced into the reaction vessel. Thevessel was then purged with nitrogen for 30 minutes while stirring andsubsequently heated to 80° C. During the heating phase, a pre-emulsionwas prepared in the feed vessel by addition of component III tocomponent II with stirring. When the temperature in the reactor reached80° C., the pre-emulsion was added over a period of 2 hours. After theaddition, the temperature was kept at 80° C. for another 2 hours. Thedispersion was then cooled. The pH value was adjusted to approx. 7 withthe 10% ammonium carbonate solution.

Example 2

Production of an ethyl acrylate/acrylic acid copolymer

The following components were initially prepared:

Component I:

662.6 g fully deionized water

3.2 g OPS 80

0.4 g NaOH (pellets) dissolved in 8.7 g fully deionized water.

Component II:

0.5 g ammonium peroxodisulfate dissolved in 8.7 g fully deionized water.

Component III:

8.0 g hydrogen peroxide (30%)

Component IV:

290.9 g ethyl acrylate

9.0 g acrylic acid.

For pH adjustment:

8.0 g conc. ammonia

Component I was initially introduced into the reaction vessel describedin Example 1. The reaction vessel was purged with nitrogen for 30minutes and subsequently heated to 80° C. Component II was added at 70°C. When the temperature in the reactor reached 80° C., component IV wasadded over a period of 60 minutes. After another 10 minutes, componentIII was added. The temperature was then kept at 86° to 87° C. foranother 40 minutes. The dispersion obtained was cooled. The pH value wasadjusted to approx. 8 with concentrated ammonia.

Example 3

Production of an ethylhexyl acrylate/methyl methacrylate/ methacrylicacid copolymer

The following components were initially prepared:

Component I:

195.6 g fully deionized water

3.5 g OPS 80 (100% AS)

0.3 g potassium peroxodisulfate

0.5 g sodium hydrogen carbonate

Component II:

245.6 g fully deionized water

1.5 g OPS 80 (100% AS)

6.2 g of a commercially available adduct of 20 mol ethylene oxide withnonylphenol (80% active substance, co-emulsifier)

1.9 g potassium peroxodisulfate

Component III:

225.4 g 2-ethylhexyl acrylate

254.8 g methyl methacrylate

9.8 g methacrylic acid

Component IV:

4.8 g potassium peroxodisulfate solution, 5%

For pH adjustment:

50.0 g sodium hydrogen carbonate solution, 10%.

Component I was initially introduced into the reaction vessel describedin Example 1. The reaction vessel was purged with nitrogen for 30minutes while stirring and subsequently heated to 75° C. During theheating phase, the pre-emulsion was prepared in the feed vessel byaddition of component III to component II with stirring.

When the temperature in the reactor reached 75° C., the monomerpre-emulsion was added over a period of 2 h. After the addition, thereaction was post-initiated with potassium peroxodisulfate solution(component IV) and the temperature was kept at 85° C. for 1 h. Thedispersion was then cooled and the pH value was adjusted to approx. 7with a 10 % sodium hydrogen carbonate solution.

Examples 1, 2 and 3 were repeated with the corresponding quantity of OPS108.

Testing of the polymer dispersions obtained produced the results set outin Table 1 (MFT=minimum film-forming temperature). The results of thefoam measurements are summarized in Table 2. The phosphate sulfonatestested proved to be low-foaming.

                  TABLE 1                                                         ______________________________________                                        Testing of the dispersions obtained                                           ______________________________________                                        Example 1         OPS 80   OPS 108                                            ______________________________________                                        Coagulate (%)     0.5      0.4                                                Dry residue (%)   49.3     49.0                                               Viscosity (mPa · s)                                                                    120      123                                                pH value          6.8      6.6                                                MFT (°C.)  14-15    13-15                                              Mechanical stability*                                                                           Stable   Stable                                             ______________________________________                                         *Addition of 0.25% by weight Dehydran G (commercially available foam          inhibitor for watercontaining systems)                                   

    Example 2         OPS 80   OPS 108                                            ______________________________________                                        Coagulate (%)     0.9      1.2                                                Dry residue (%)   29.6     29.5                                               Viscosity (mPa · s)                                                                    17.5     17.5                                               pH value          8.1      8.3                                                MFT (°C.)  0        3                                                  Mechanical stability*                                                                           0.1      0.1                                                ______________________________________                                         *Addition of 0.25% by weight Dehydran G (commercially available foam          inhibitor for watercontaining systems), % by weight coagulate            

    Example 3         OPS 80   OPS 108                                            ______________________________________                                        Coagulate (%)     0.1      0.2                                                Dry residue (%)   50.2     50.1                                               Viscosity (mPa · s)                                                                    40       40                                                 pH value          7.4      7.2                                                MFT (°C.)  34-36    34-36                                              Mechanical stability                                                                            Stable   Stable                                             ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                        Results of foam measurement                                                   Compo- Formu-     Total volume                                                nent   lation     0'     1'     3'   5'     20'                               ______________________________________                                        OPS 80 I          1980   1940   1800 1600   600                               OPS 108                                                                              I          1960   1920   1820 1500   600                               OPS 80 II          800    400    400  380   --                                OPS 108                                                                              II          900    440    380  380   --                                OPS 80 III        1540   1400   1080  700   400                               OPS 108                                                                              III        1900   1600    700  600   400                               ______________________________________                                    

We claim:
 1. In the emulsion polymerization of one or more monomers inwhich at least one of the monomers is substantially water insoluble, theimprovement wherein the emulsion polymerization reaction mixturecontains an emulsifying effective quantity of at least one salt of asulfonated alkenyl or alkenyl (poly) oxyalkyl phosphate of formula I

    [R.sup.1 O--(CH.sub.n H.sub.2n O).sub.x --][R.sup.2 O--(C.sub.n H.sub.2n O).sub.y--][R.sup.3 O--(C.sub.n H.sub.2n O).sub.z --]P═O(I)

in which R¹ is a group corresponding to formula IIa or IIb

    CH.sub.3 --(CH.sub.2).sub.a --CH(OH)--(CH.sub.2).sub.b --CH(SO.sub.3 M)--(CH.sub.2).sub.c --CH.sub.2 --                        (IIa)

    CH.sub.3 --(CH.sub.2).sub.a --CH(SO.sub.3 M)--(CH.sub.2).sub.b --CH(OH)--(CH.sub.2).sub.c --CH.sub.2 --                  (IIb)

or is a residue formed by elimination of one water molecule from thegroup corresponding to formula IIa or IIb, R² and R³ may be the same ordifferent and represent hydrogen or a residue having the meaning givenabove for the group R₁, n is the number 2 and/or 3, x, y and z may bethe same or different and represent numbers of 0 to 100 a, b and c arenumbers of 0 to 18, the sum of a, b and c being a number of 12 to 18,and M is an alkali metal ion, the ammonium ion, a protonated amine ion,or an equivalent of an alkaline-earth metal ion.
 2. The process of claim1 in which the compound of formula I x, y and z represent numbers offrom 0 to
 30. 3. The process of claim 1 wherein in the compound offormula I, the R¹ group is salt of a sulfonated oleyl group, R² and R³are hydrogen or a salt of a sulfonated oleyl group, n is the number 2,and x, y and z are numbers of from 0 to
 20. 4. The process of claim 1wherein in the compound of formula I, M is the sodium ion.
 5. Theprocess of claim 3 wherein in the compound of formula I the salt is thesodium salt.
 6. The process of claim 1 wherein the emulsifying effectivequantity is from about 0.5 to about 10% by weight, based on the weightof monomers.
 7. The process of claim 6 wherein the emulsifying effectivequantity is from about 1 to about 5% by weight, based on the weight ofmonomers.
 8. The process of claim 6 wherein the emulsifying effectivequantity is from about 1 to about 3% by weight, based on the weight ofmonomers.
 9. The process of claim 1 in which the emulsion polymerizationprocess is carried out at a temperature in the range of from about 40°to about 100° C.
 10. The process of claim 9 wherein the temperature isin the range of from about 50° to about 90° C.
 11. The process of claim1 wherein the pH of the emulsion polymerization reaction mixture is fromabout 3 to about
 9. 12. The process of claim 1 wherein another anionicemulsifier is also present in the emulsion polymerization reactionmixture.
 13. The process of claim 1 wherein from about 0.5 to about 5%by weight, based on monomers, of a nonionic emulsifier is also presentin the emulsion polymerization reaction mixture.
 14. The process ofclaim 1 wherein the emulsion polymerization reaction mixture alsocontains a protective colloid.
 15. The process of claim 1 wherein theemulsifying effective quantity is from about 0.5 to about 10% by weight,based on the weight of monomers; in the compound of formula I the R¹group is a salt of a sulfonated oleyl group, R² and R³ are hydrogen or asalt of a sulfonated oleyl group, n is the number 2, and x, y and z arenumbers of from 0 to 10; and the emulsion polymerization process iscarried out at a temperature of from about 40° to about 100° C.
 16. Theprocess of claim 15 wherein the process is carried out at a temperatureof from about 50° to about 90° C. and at a pH of from about 3 to about9.